Stitch-forming mechanism for sewing machines



NOV. 11, 1930. w B N 1,781,427

STITCH FORMING MECHANISM FOR SEWING MACHINES FiledOct. 26, 1928 2 Sheets-Shed 1 F 3 gmentoo {7 William [M Nov. 11, 1930. w. BARRON STITCH FORMING MECHANISM FOR SEWING MACHINES 2 Shaets-Sheet' 2 Filed Oct. 26, 1928 I flz'lliamLJa/wb entree STATES WIiLLIAM L. BARRON, OF LAURENCE HARBOR, NEW JERSEY, ASSIGNOR TO THE SINGER Patented Nov. 11, 1930 PATENT GFFICE MANUFACTURING COMPANY, OF ELIZABETH, JERSEY, A COR?BATION" OF NEW JERSEY 1 STITCH-FORMING MECEANISM FOR. SEVJING MACHINES Application filed ember 26,1928, Serial No. 315,114.

This invention relates ,to sewing machines, more particularly of the rotary hook type .disclosed, for example, in the patenttoMartin Hemleb, No. 1,149,049 of Aug. 3,1915, and has for an object to provide a machine of thistype with means for assisting the needle in throwing out its loop, while maintaining the freest possible provisionfor maxainount'by which the needle-loop canbe free lycontracted after the hook reaches castoft position, and before the opening of the usual.

gap in the bearing between the thread-case andhook for final escape of the needle-loop. In the machine of saidfl lemleb patent there is a thread-caserotation-restraining bar formedin one edge with two notches. One of these notches is for clearance of the needle and the nascent. needle-loop. The other notch,.which is disposed atone side of the needle-clearance notclnris entered by a lugfon the thread-case to restrainthe latter from rotation with the hook. It has been tound desirable to add to the thread-case of the machiueio't said Hemleb patent asecond. lug, disposed alonn'side the rotationrest raining lug and opposi ethenwuthoit' the. needleclearance notch, to function as a stop. for preventing expansion of the nascent needle loop on the wrong side of the needle and to force the needle-loop to expand primarily on the side of the needle passed by the loop' seizing beak of thehook. The requirement for the needle-loop stop further hampers the machine for embroidery work, as it limits the size to which the cast needle-loop can be contracted prior to its final escape from the thread-ease.

.Accordingto the present improvement, the

customary needle-loop stop is omitted but its'desirable iunctlon is retained by constructing the thread-case rotat on-restrailling bar witha. single notch having both needledoop to its final escape from the thread-case, thus improving the o 'ierating characterlstics oi the stitclnforming mechanism, more particularly for embroidering operations.

In the accompanying drawings, Fig. 1 is a side elevation, partly in section, of a rotary hook stitch-forming mechanism embodying the invention. Fig. 2 is a plan View of the rotary hook and thread-case elements of the mechanism. Fig. 3 is a section on the line, 33, Fig. 1. Fig. 4-. is a side elevation of the thread-case. Fig. 5 is a bottom plan View of the thread-case. Fig. 6 is a perspective view of the stitchforming mechanism showing the needle-loop escaping from the threadcase. Fig. 7 is a plan view of the rotaryhook, and Fig. 8 isa plan view of the rotation-restraining bar. y

In thepreterred embodiment oi the invention illustrated, 1 represents the bed of a SEWlllgllltlClllHQ andQ the head of the usual gooseneek in which is mounted the reciproeating needle bar 3 carryingthe eyerpointed needle 4. The bed .1 carries the usual throat;

plate Shaving: slots 6 in whiclrthe four-mo;- tion icedfdogi' operates. As the present machine is fitted for embroidering, the teecl+dog 7 is coyeredpand rendered ineffective by the feed-cover plate 8 upon whichthe fabric 9 is pressed intermittently by a suitableembroidery presser 10; the one shown having downwardly spring-pressed shank 11 slidably mounted in a vertical guide 12 carried by the presser-bar 13. The shank 11 has fixed to its upper end an arm M which overhangs the needle-clamp-screw 15 and is engaged by the latter as the needle-bar 3 near the end of its upstroke, thereby lifting the foot to tree the workfor"hand-manipulation of the latter.

, vGeope -ati ng with-the needle 4 is the rotary tinder-thread mechanism ncluding the cup- U shaped i'otajry-hook-body 16 carried by the vertical. shaft; 17' and formed" with a loop seizing beak 18 and .a bearing supportv 19 for the flange 20 of the thread-case 21 having the usual pocket tor'the bobbin 22. The' bearing fli z g 20bit the thread-case is not continuous but isfforined adjacent the path of the needle 4 with a gap 23 forescape of the needle-loop,

when saidfgap is opened by passage of the trailing end24 of the bearing 19 of the hook- Screwed to the under sides of the bed-lugs 25 are the ends of the thread-case rotation restraining bar. 26 formed in one'edge with a about the screw 34- on the thread-case and hearing at one end against the lug30 engages the tailr31 of the finger and yieldingly presses it outwardly against the side oi the hole The 'finger 28 is curved convex'ly towardfa "line aa joining the axis 0 of the hook with the needle-pathp. This direction ofcurvature facilitates the contraction of the needle loop and the ready escape of they latter:

through the curved gap 36 to be referred to. In the operation oil? the machine, the trio 1 tional drag of the hoojk body Upon the thread i case maintains-the finger-end 28in engage nent with the side 35 cf the mouth ,of the notch 27 in the 1;otatiion-restrainingbar 26 :leaa'inga narrow curved gap 36 Fig, 2, be tween the curved finger end 28 and the other side 35 of the inouth of the notch 27, The

' side .35 of the month ofgthe notch 27fis closed i h e xp ded z dleel opu -fi'se, t be '24 of ,thethread-case hearing Jo h hack-f "body n a yea a ng Open th g pfl ap 23 ;ifl S4-i euni pgth ll hj nswers easmeae n e ontra ed, s byga manu sh ft he. Work, 7

f0 te l1iI1 'P Si D 8" h t ai ng. nd

and the bar 26, as shown in F igi 6, after which the needle-loop is pulled up between the finger 28 and the side 35 of the mouth of the notch 27; the finger 28 yielding about its pivot 29 to open agap for theneedle-loop,

without necessitating a shift of the entire thread-case. H v V Theinventi'on is notto bennderstood as limited to the exact form and arrangement of parts shown and described these'iina y obviously be variously modified within the scope of'the invention by one skilled in the art. o

' Having thus set forththe nature of the invention, what I claim herein is z' '1; In a sewing machine, a reciprocating needle, a rotary hook having a loop-taking beak, a bobbin-case, a bobbin-case rotationrestraining ele1nent havi-ng'a notch embracing the needle-path, said notch having an open mouth at one side of theneedle-path" and a close'd 'bottomed throat at the'oppositesi-de of the'needle-path, at'which opposite side the beak of the hook is arranged to pass in takinga needle-loop, and means on the bobbin case entering the inouth of said notch to restrain the 'bobb'in case 'fr'oin rotation.

c 2. In 7 a sewing 'machin, a reciprocating needle, a throat-plate, rotary hook having a loop-taking beak, a bobbin-case, a bobbincase rotationrestraining bar spaced below the under surface of the'throat-plate and close to the path otthellooptaking 'beak,a feed-dog overhanging said rotation-restraining bar, said bar havinga notch in one edge path and a closed-bottomedthroat at the op- 7 1m embracing the needle path,.sa1d notch having an open-month at one side 'ofthe needleposite side'of. the needle-path', at which op I posite side'the-lhook beak is arranged to pass in taking aneedle-loop, and means on the" bobbin-caseenteringthe mouth of said notch torestrain the bobbin-case'from rotation.

:3; In a' sewing machine, a rec procating needle, a -rotary 'hoolga"bobbin-case, abobance throat at the same side of the needlepath passed ,by the hook-beak, and means on .r r bin-case*rotat on restra1n1ng bar-having in one edge a needle-clearance notch deepened the bobbin-case entering the mouth of said notch in {position to engage one'liinb of the nascent needle-loopan'd function" as a 7 stop in h o herxlimbof the needle-loop to 7' bow into {the closed bottomed throat of the notch in said rotationres'training ibar.

name'to this'specification.

,e-curveodi ep 'ln testi'mony whereof, T'have signed my 

